"Lindsay is very upset that the judge ordered her to go straight to rehab," a source tells PEOPLE.
The actress, 24, was released from a Lynwood, Calif., jail early Monday morning after serving 13 full days of a 90-day sentence for violating probation in a DUI case. She was directly sent to rehab at UCLA Medical Center, where she is required to complete a three-month inpatient stint, according to Judge Marsha Revel's sentencing order.
Though her mom Dina and younger sister Ali met up with Lohan at UCLA on Monday, "[Lindsay] feels that she deserved to spend a day with her family after she behaved well in jail," says the source.
Lohan, the source adds, is feeling "depressed." "[She] is having a difficult time accepting that she will be in rehab for the next three months," the source says. "She still doesn't think that she needs any help."